The present invention relates to the manufacture of man-made filamentary material and, in particular, to the application of a finishing liquid to the filamentary material.
The manufacture of man-made filamentary material is achieved, for example, by extruding a molten polymer, such as polyester, polyamide, etc., through a spinneret and then cooling the filamentary material thus formed. At some point in the process a finishing liquid may be applied to the filamentary material in order to impart a desired property thereto, such as smoothness, drape, luster, water repellency, flame retardancy, and crease resistance, for example. It will be appreciated that the quality of the filamentary material thus produced is affected by the uniformity of the application of the finishing liquid.
It has been heretofore difficult to achieve a uniform application of the finish fluid onto the filamentary material, which may be in the form of individual filaments or bundles of filamentary yarn. That difficulty intensifies with increases in denier and/or running speeds and is not alleviated by conventional finish applicators in which filaments or filamentary yarn bundles are gathered together and sprayed with finish. It is difficult in such a case to uniformly reach all of the filamentary material with finish liquid. Furthermore, there often occur pulsations in the flow of finish liquid through the spray passages or capillaries, whereby the application of the liquid becomes non-uniform along the longitudinal dimension of the filamentary material, i.e., in the direction of filament travel.
It is, therefore, an object of the present invention to provide novel methods and apparatus for applying a finish fluid to filamentary material in a more uniform manner.
An additional object is to minimize or prevent the occurrence of pressure pulses or surges in the capillaries which conduct the finish liquid.